Air Masses & Weather Patterns

Question of the Day

What is an Air Mass?

Air Masses

Movements of large bodies of air that originate at a source region

Characterized by temperature and moisture content

Important because they cause atmospheric disturbances

Classifying Air Masses

Depends on latitude and nature of surface of source area -Latitude P(polar), A(arctic), T (tropical) -Nature of Surface m(maritime), c(continental)

Midlatitudes

Regions between southern Florida and Alaska.

Primary weather producer is middle-latitude cyclone (low pressure system by meteorologists)

Fronts

Boundary surfaces that separate air masses from different densities. One is usually warm and has more moisture than the

other Overrunning is when warmer, less dense air is forced

up along the colder, more dense air 5 different types of fronts

Warm Cold Stationary Occluded Drylines

Warm Fronts

Warm surface air replaces area where cooler air was

Red line with semicircles on a weather mapChange in types of clouds as front

approachesLight to moderate precipitation over a large

area and for an extended period of time

Cold Front

Cold air moves into region where warmer air is

Blue line with triangles on a mapHeavy Precipitation over a shorter duration

and gusts of windCooler temperatures after storm clears

Stationary Front

Cold Mass and Warm Mass air meetLine with blue triangles and red semicircles

on mapNo movement or slow movement of air

masses so gentle/moderate precipitation for days

Occluded Fronts

Fast moving cold front over takes a warm front

Heavy rain at first then light rain as it dissipates.

Can have cold-type and warm-type occluded fronts

Drylines

Based upon humidityGenerate severe thunderstorms from Texas to

Nebraska along Great Plains